Dipole rectification in an oscillating electric field

¹  School of Mathematics, Loughborough University - Loughborough LE11 3TU, UK, EU
²  Dipartimento di Fisica, Università di Camerino - I-62032 Camerino, Italy, EU
³  Department of Physics, Loughborough University - Loughborough LE11 3TU, UK, EU

Received: 14 September 2009
Accepted: 16 October 2009

Abstract

Directed transport of a neutral dimer driven by an ac electric field on a one-dimensional asymmetric substrate is demonstrated. We specialize on the case of a short elastic dimer formed by two bound equal masses carrying opposite charges, i.e., a dipole. The combination of ac drive and binding potential induces a net dipole current (strictly zero for a rigid dimer), which can be optimized by tuning the temperature and the driving frequency with distinct activation energies. Under appropriate operating conditions, a dimer can get rectified more efficiently than its constituents set free, thus implying that particle pairing can actually enhance the ratchet effect.